Safety Requirements and Test Methods for Lithium Ion Power Battery Packages and Systems for Electric Vehicles
With the popularization of electric vehicles (EV), lithium-ion power battery pack, as its core energy unit, has become the focus of the industry and regulatory agencies. Although lithium-ion batteries have high energy density and good cycle performance, they also have potential safety hazards such as overheating, short circuit and mechanical damage in practical applications. In order to ensure the operation safety of electric vehicles, it is particularly important to formulate scientific and reasonable safety requirements and testing methods. This paper focuses on the safety requirements of lithium-ion power battery package and system for electric vehicles, and elaborates in detail in combination with relevant testing methods.
I. Basic safety requirements of lithium ion power battery package for electric vehicles
electric vehicle power battery pack is an energy system integrated by multiple lithium-ion battery monomer through reasonable design. The main safety requirements include electrical safety, thermal safety, mechanical safety and environmental adaptability.
1. Electrical Safety
- overcharge and overdischarge protection: battery pack must have a complete voltage monitoring and management system to prevent single battery overcharging (voltage exceeds the designed upper limit) or overdischarging (voltage is lower than the safety lower limit), avoid shortened battery life or safety accidents.
- Short circuit protection: whether it is an internal short circuit or an external short circuit, battery pack should have a quick open circuit mechanism to prevent thermal runaway caused by large current.
- Battery Management System (BMS): BMS needs to monitor the voltage, current, temperature and other key parameters of the battery in real time to respond to abnormal conditions in time to ensure that the battery is in a safe range.Run in.
2. Thermal Safety
- temperature control: battery pack an effective thermal management system should be designed to achieve uniform heat dissipation and prevent local overheating. Excessive temperature may cause thermal runaway, leading to combustion or explosion.
- Thermal runaway prevention measures: reduce the risk of thermal runaway by means of material selection and structural design, such as flame retardant materials and insulation layers.
- Temperature Monitoring: set temperature sensors in key parts, feed back battery pack temperature in real time, and assist BMS to adjust the running status.
3. Mechanical safety
- impact resistance: battery pack should be able to withstand mechanical shocks such as collision, vibration and compression to prevent short circuit or leakage of the battery caused by structural damage.
- Puncture-proof design: battery pack the shell and internal structure must have puncture-proof performance to reduce the risk of safety accidents caused by the penetration of external sharp objects.
- Sealing: good sealing design can prevent water vapor, dust and corrosive gases from entering, prolong battery life and ensure safety.
4. Environmental adaptability
II. Safety test method of electric vehicle power battery package
in order to verify that the dynamic battery pack meets the above safety requirements, systematic and scientific tests must be carried out. The following are common security testing methods:
1. Overcharge test
simulate the performance of battery pack single battery under abnormal charging. Through continuous charging, the battery voltage exceeds the designed upper limit, observe whether there are phenomena such as expansion, leakage, smoke and even combustion in the battery pack, and evaluate the effectiveness of the protection system.
2. Over-release test
Simulate the state of the battery pack battery during excessive discharge. Test the battery behavior after exceeding the discharge cut-off voltage to ensure that the internal structure of the battery will not be damaged or potential safety hazard caused by over-discharge.
3. External short circuit test
short-circuit the positive and negative poles of battery pack to check battery pack ability to cope with large current. Monitor temperature changes and voltage fluctuations during testing to ensure that the protection device can disconnect the circuit in time to prevent catastrophic failures.
4. Internal short circuit test
the battery failure status is simulated by artificially manufacturing the internal short circuit defect of the battery cell. This test evaluates the response and control ability of battery pack and BMS to internal short circuit, and is an important means to test the risk of thermal runaway.
5. Thermal shock test
place battery pack in a high temperature environment to simulate extreme weather or equipment heating. Test the temperature resistance of battery pack thermal management system and materials to verify whether there are potential safety hazards.
6. Mechanical shock and vibration test
7. Puncture test
puncture battery pack with sharp objects to test its puncture resistance and battery reaction. This test reflects the safety performance of battery pack in extreme accidents.
8. Waterproof and dustproof test
according to the IP level standard, test the sealing performance of battery pack. Spray, soak and Dust Environment tests to ensure that battery pack will not be damaged in harsh environments.
9. Comprehensive safety performance test
combined with the above tests, comprehensive tests such as cyclic charging and discharging for a long time and environmental simulation are carried out to evaluate the safety and stability of battery pack under actual use conditions.
III. Safety assurance function of battery management system (BMS)
BMS is a lithium ion dynamicThe brain battery pack runs safely. Its functions include:
- monitor the voltage, temperature and current of single battery in real time, and detect abnormalities in time.
- Balance charging to avoid overcharging or overdischarging of single battery.
- Control the charging and discharging process to prevent short circuit and overload.
- Early warning and protection mechanisms, including open circuit, power reduction, etc., to prevent accidents from expanding.
- Record battery operation data to provide basis for maintenance and fault diagnosis.
Greatly improved through intelligent management of BMS power battery pack security and reliability.
The safety of lithium-ion battery pack and system for electric vehicles is the key to ensure the performance of the whole vehicle and the safety of users' lives and property. Its safety requirements cover electrical, thermal, mechanical and environmental adaptation, which must be verified by strict testing methods. The perfect battery management system provides technical guarantee for the safe operation of battery pack.
Dongguan Juneng New Energy Technology Co., Ltd.
137 5142 6524（Miss Gao）
susiegao@power-ing.com
Xinghuiyuan High tech Industrial Park, Dalang Town, Dongguan City, Guangdong Province
Yue Gong Wang An Bei No. 4419002007491